How Short And Intense Workouts Changed Fitness For Everyone

David Tao
, ContributorI write about the intersection of fitness and business.Opinions expressed by Forbes Contributors are their own.

Fitness is tough. So when someone claims they’ve found a “scientifically proven” shortcut to bigger biceps, better endurance, and a sexier core, we’re usually right to be skeptical. Conventional workout wisdom says that if you want to dominate a marathon, you better get ready to run far and often.

But methods bucking this conventional take are gaining serious mainstream traction — with the scientific evidence to support some counter-intuitive conclusions. Long, slow runs are pretty good at building endurance for long, slow runs. It’s becoming increasingly clear, though, that shorter, more intense bouts boost both short term and long-term exercise capacity, resulting in more efficient workouts that take a fraction of the time.

The rise of high-intensity interval training — usually maximal-effort sprints mixed with lower-intensity rest periods, repeated for a number of sets — is in part thanks to Dr. Izumi Tabata, a Japanese researcher whose mid-1990s work with Olympic speed-skaters resulted in the “20 seconds on, 10 seconds off” protocol that bears his name. I’ve written about Tabata Protocol for Greatist on numerous occasions; basically, exercisers work all-out for 20 seconds, rest for 10 seconds, then repeat for eight total sets. The whole endeavor takes just 4 minutes and has been shown in multiple research trials to significantly boost endurance, even beyond steady state cardio totaling 30 minutes or more. Beyond the time factor, a big part of Tabata’s appeal is its flexibility. The protocol can be used running, swimming, biking, or while performing weighted or bodyweight resistance movements (push-ups are a personal favorite).

Dr. Tabata’s method is just one of many high-intensity interval programs that have gained popularity over the past decade, and the business of fitness is adapting in kind. Some of today’s most popular workout methodologies — most notably CrossFit, which occasionally includes Tabata intervals — are based on the scientific superiority of very high-intensity work over long, slow slogs. Fitness pros from elite coaches to beach-body bootcamps are upping intensity and shortening workouts to get clients better results, and Dr. Tabata himself is in talks to develop a fitness DVD series with Universal Studios. As trainer Rob Sulaver explains in an upcoming article from Schwarzenegger.com:

Back in the day we realized that proportionally, we burn more calories from fat at lower intensities. We aptly named this the “fat burning zone.” Get on an old-school piece of cardio equipment and you’ll see that the lower heart rate zone is labeled “fat burning.” But we made a colossal mistake. It’s not that we were wrong, necessarily. It’s that we were looking at the science through a straw. Yes, we burn more calories proportionately from fat at lower intensity, but we burn far more calories, period, at higher intensity. In other words, if you want to burn fat…the most effective “fat burning zone” is…higher intensity training.

Of course, this shift in methodology hasn’t been smooth across the board. Beyond having to learn and prescribe entirely new routines, fitness professionals have to be careful introducing clients to workouts that leave many on the floor gasping for breath (when Dr. Tabata calls for "all-out" sprints, he means just that). According to Tony Gentilcore, a Boston-based trainer and coach to numerous professional athletes, upping intensity can also add to the risk for exercise-related injuries.

“Given the time constraints that many people have today…shorter, more ‘intense’ metabolic based routines do come in handy,” writes Gentilcore. “But at the same time, when you combine people who don't necessarily move too well and have limited ranges of motion with high velocity movements which are more technical in nature, it could make for a highly volatile situation where someone can really hurt themselves.”

Gentilcore cautions the popularity of high-intensity interval training could push some gyms and studios to develop “cookie-cutter” circuits of moves that get a lot of people through their doors in record time. While performing those movements at high intensity might work wonders for one person, the same routine could put another in harm’s way.

Ultimately, the proliferation of interval training and other high-intensity protocols has saved a lot of time and burned a lot of fat for fitness enthusiasts worldwide. And there’s an increasingly large body of evidence to back up its effectiveness, whether it’s Tabata on a treadmill or a well-designed CrossFit WOD. But while fitness instructors have had to radically update their knowledge bases in order to keep up with research — a truly positive development — their responsibility to keep clients safe has become even more pronounced.

Interval training has helped usher in a brave new world of science-based fitness. But that progress won’t turn us all into elite athletes overnight, and like all things in fitness, high-intensity training isn't a one-size-fits-all approach. Fitness today might be more a series of sprints as opposed to yesterday's long jog, but it will never be a walk in the park.

What are your thoughts on high-intensity training? Sound off below and follow the author @d_tao.